1. Field of the Invention
The present invention relates to an assist tool attachable to an insertion section of an insertion apparatus, an insertion apparatus to which the assist tool is attached, and an introduction apparatus including them.
2. Description of the Related Art
An assist tool to be attached to an insertion apparatus, for example, an insertion section of an endoscope is known. The assist tool assists insertion of the insertion section into a body cavity. For example, US2012/0029281 discloses an apparatus for accessing a bodily passageway, the apparatus comprising an endoscope including an insertion section, and a rotation unit including a disposable drive tube attached to an external circumferential surface of the insertion section. A spiral fin is provided on an external circumferential surface of the drive tube. In the endoscope, a drive unit is provided to transmit a drive force to the rotation unit. Furthermore, a plurality of rollers abutting against the drive unit is provided on an internal circumferential surface of the drive tube.
In the apparatus, when the rotation unit is attached to the insertion section of the endoscope, the drive tube is rotated around a central axis thereof by a drive force transmitted from the drive unit to the drive tube via the rollers. For example, when the apparatus is used for inspection, diagnosis, or treatment of a serpentine long organ, such as the small intestine and the large intestine, the insertion section of the endoscope advances into deep distal sites, while pressing the wall abutting against the spiral fin of the rotating drive tube, such as the small intestinal wall and the large intestinal wall, toward the proximal end.